1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
tamaranim1 [39]
2 years ago
5

The door is 3.00 m tall and 1.25 m wide, and it weighs 750 N . You can ignore the friction at the hinges. If Exena applies a for

ce of 220 N at the edge of the door and perpendicular to it, how much time does it take her to close the door?
Physics
1 answer:
Marat540 [252]2 years ago
4 0

Answer:

0.674 s = t

Explanation:

Assuming that the door is completely open, exena need to rotate the door 90°.

Now, using the next equation:

T = I∝

Where T is the torque, I is the moment of inertia and ∝ is the angular aceleration.

Also, the torque could be calculated by:

T = Fd

where F is the force and d is the lever arm.

so:

T = 220N*1.25m

T = 275 N*m

Addittionaly, the moment of inertia of the door is calculated as:

I = \frac{1}{3}Ma^2

where M is the mass of the door and a is the wide.

I  =\frac{1}{3}(750/9.8)(1.25)^2

I = 39.85 kg*m^2

Replacing in the first equation and solving for ∝, we get::

T = I∝

275 = 39.85∝

∝ = 6.9 rad/s

Now, the next equation give as a relation between θ (the angle that exena need to rotate) ∝ (the angular aceleration) and t (the time):

θ = \frac{1}{2}∝t^2

Replacing the values of θ and ∝ and solving for t, we get:

\sqrt{\frac{2(\pi/2)}{6.9 rad/s}} = t

0.674 s = t

You might be interested in
PLEASE I NEED HELP
777dan777 [17]

Answer:

K= 95.4 J

Explanation:

For this exercise we must use the conservation of mechanical energy.

We set a reference system on the floor.

Starting point. Higher

          Em₀ = U = m g h

Final point. Just before taking the floor

           Em_f = K = ½ m v²

energy is conserved because there is no friction

         Em₀ = Em_f

         mg h = K

         

The height is

  1.         h = y -y₀

                 h = 0- y₀

let's calculate

       K =  3.23 (-9.81)  (-3.01)          

       K= 95.4 J

5 0
2 years ago
Which of the following statements is FALSE?
kobusy [5.1K]
The false statement would be :
C. constructive interference occurs when the crest of one wave overlaps the trough of another and their individual effects are reduced or cancelled out.

Constructive interference should be when the crest of one wave overlaps another and their individual effects are add up, becoming a single wave of increased amplitude<span />
6 0
3 years ago
A car is traveling at a speed of 38.0 m/s on an interstate highway where the speed limit is 75.0 mi/h. Is the driver exceeding t
lidiya [134]

Answer:

Yes, the car driver is exceeding the given limit.

Explanation:

<u>Given:</u>

  • Speed of the car, v = 38.0 m/s.
  • Speed limit of the highway, \rm v_o=75.0\ mi/h.

<h2><u>Converting the speed limit from mi/h to m/s:</u></h2>

We know,

1 mi = 1.60934 km.

1 km = 1000 m.

Therefore, 1 mi = 1.60934 × 1000 m = 1609.34 m.

1 hour = 60 minutes.

1 minute = 60 seconds.

Therefore, 1 hour = 60 × 60 seconds = 3600 seconds.

Using these values,

\rm 1\ \dfrac{mi}{h}=\dfrac{1609.34\ m}{3600\ s}=0.447\ m/s.

Therefore,

\rm v_o = 75.0\ mi/h=75.0\times 0.447=33.52\ m/s.

Clearly,

\rm v_o

which means, the car driver is exceeding the given speed limit.

6 0
3 years ago
A rock is thrown horizontally from a building at 15 m/s. It hits the ground 45 m from the base of the building. How high was the
evablogger [386]

Answer:

Explanation:

hope this helps!

7 0
2 years ago
All please..............
rodikova [14]
4 water has a low heat capacity and a high vaporization temperate and coasts have low temps
3 0
3 years ago
Other questions:
  • Joanna has become good friends with Janna, whose name begins with the same letter as hers. They sit next to each other in three
    9·2 answers
  • Two long, parallel wires separated by 5.0 mm each carry a current of 60 A. These two currents are oppositely directed. What is t
    14·2 answers
  • a body of mass 5kg falls from height of 10m above the ground what kinetic energy of the body before it strike the ground
    6·1 answer
  • sky divers jump out of planes at an altitude of 4000m. How much timewill passuntill they deploy their parachutes at an altitutde
    12·1 answer
  • You are driving at 35 m/s east and notice another car that is initially located 462 m in front of you and is moving east at 25 m
    13·2 answers
  • g f, as a pioneer, you wished to warm your room by taking an object heated on top of a stove into it, which of the following 15
    13·1 answer
  • Question 3 (10 points)
    5·1 answer
  • 4. A microchip lets computers process information very quickly,
    10·1 answer
  • What is common in elastic collision, inelastic collision and perfectly inelastic collision​
    7·2 answers
  • Scientists might live too far away to meet face to face. What are the three other ways they can share data and discuss evidence?
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!